It looks like he did good coverage on the way up the field then did bad coverage on the way down the field, hence we have some good patches which are well grown and some really bare patches. So I think it was his technique that was bad rather than the soil.
What we are planning to do is fence off one acre and put the sheep in it, with regular hard feed and hay and overseed the other 3 acres and leave as long as possible, probably until lambs are weaning, then just let them have one of the new acres, overseed the first, and carry on growing the other 2 acres
Will take time to get it sorted but I spose we'll get there.